First move the SetArmour method into your MyCharacter blueprint, and have all the functionality there. You can remove the Cast entirely when that is done.
Then create two new methods, one for equipping armour and one for equipping a weapon; and move the functionality you have in your button click events into them.
In your widget, keep the same PlayerRef, but have your button clicks call your new EquipArmour and EquipWeapon methods.
I’ll give you pics in a bit.